The role of orthophosphate in crossbridge kinetics in chemically skinned rabbit psoas fibres as detected with sinusoidal and step length alterations

Summary The role of orthophosphate (P_i) ions in crossbridge kinetics was investigated in chemically skinned rabbit psoas fibres in the presence of saturating Ca²⁺. The muscle length was altered sinusoidally, and the resulting tension time courses were analysed in terms of three exponential processes (A), (B) and (C). Experiments were also performed with step length changes, and the resulting tension transients were correlated with the results of sinusoidal analysis. It was shown that addition of a low millimolar concentration of P_i increased both the rate constant and magnitude of process (B), which resulted in a dramatic increase in the oscillatory power output. The P_i effect was greater at higher oscillation amplitude and at higher MgATP concentration. At 5mm MgATP, the amplitude effect became saturated at a 6 nm length change per crossbridge, whereas the P_i effect did not become saturated in the concentration range tested (0–16mm), An introduction of MgADP to the activating saline resulted in a decrease of all rate constants, and these effects were opposite to MgATP. The effect of P_i resembled neither MgADP nor MgATP. Based on these observations, all the crossbridge reactions except for one (ADP desorption reaction) were eliminated as the possible site of action of P_i ions, supposing that P_i affects only one specific site in the crossbridge cycle. Other mechanisms, which might account for the P_i effects, are the presence of parallel hydrolysis pathways and the presence of multiple sites of action of the P_i ions.     

Regulation of renin-like enzyme in cultured human vascular smooth muscle cells

Cultured human arterial smooth muscle cells produced an immunologically specific renin-like enzyme. The renin-like enzyme in the culture medium was mostly an inactive form; the proportion of the active form in the cell was 30 to 75%. Phorbol 12-myristate 13-acetate, N'-O'-dibutylyladenosine 3', 5'-monophosphate and isoproterenol with theophylline increased the renin-like enzyme in the medium and in the cell, dose dependently. Endothelial cell growth supplement also increased the renin-like enzyme produced by cultured vascular smooth muscle cells, and heparin promoted the effects of endothelial cell growth supplement. The existence of the regulation of the renin-like enzyme produced by cultured vascular smooth muscle cells strongly suggests the existence of a local renin angiotensin system in human vascular walls.     

Nerve repairs for traumatic brachial plexus palsy with root avulsion

Thirty-six patients with traumatic brachial plexus lesions and root avulsions were treated surgically between 1972 and 1986 and were followed for more than 24 months (average, 42.6 months). Neurotization of the musculocutaneous nerve with intercostal nerves or the spinal accessory nerve resulted in satisfactory elbow flexion in 21 of the 33 cases (64%). Combined nerve repairs (i.e., intercostal and spinal accessory neurotization of the terminal branch of the brachial plexus in combination with nerve grafts from the upper spinal nerves of the brachial plexus) created a useful function in at least one functional level of the upper limb for 11 of the 15 cases so treated. Nerve repairs resulted in stability of the shoulder and elbow function controllable with a sensible hand for patients with root avulsion injury of the brachial plexus.     

Prognosis for patients with carcinoma in the middle third of the stomach

In 268 of the 1,115 patients (24.0%) with gastric cancer who underwent a curative resection in our clinics, the tumor was located in the middle third of the stomach. The clinicopathological features and prognosis of these patients were divided into two groups, according to site of the tumor: anterior wall (n = 58) vs. other sites (n = 210). Clinicopathological factors did not differ between the two groups. The survival time for patients with a tumor in the anterior group was shorter than that for patients with a tumor in other areas (P < 0.05). The five-year survival rate was 79.3% for patients with an anterior tumor and 91.9% for those with a tumor at a different site. A multivariate analysis indicated lymph node metastasis, serosal invasion, and anterior wall location to be independent prognostic factors indicative of a poor prognosis when the tumor was located in the middle third of the stomach. For such patients, close follow-up is needed to detect possible recurrences. © 1993 Wiley-Liss, Inc.     

Advantages of using the midline incision right retroperitoneal approach for abdominal aortic aneurysm repair

This study was conducted to compare the midline incision right retroperitoneal approach for repairing abdominal aortic aneurysms (AAA) with the transperitoneal approach. The intra- and postoperative course of 15 patients who underwent AAA repair using the transperitoneal approach between 1987 and 1991 and another 15 patients who underwent AAA repair using the retroperitoneal approach between 1991 and 1994 were evaluated. The incidence of postoperative wound complications was also assessed. There was no operative or hospital death in either group. Although a significantly longer interval was required from the incision to the aortic clamp using the extraperitoneal method, there were no statistical differences in the aortic clamping time, total operation time, or blood loss between the two groups. On the other hand, there was a statistically significant improvement in bowel function and a significant reduction in the length of postoperative hospitalization following the extraperitoneal procedure. Furthermore, no wound complications such as those associated with the left flank incision developed after the extraperitoneal procedure. Thus, we recommend the midline incision right retroperitoneal approach for AAA as it does not involve muscle division and is associated with fewer complications.     

Chronic Antibody Mediated Rejection of Renal Allografts: Pathological, Serological and Immunologic Features in Nonhuman Primates

The pathogenesis of late renal allograft loss is heterogeneous and difficult to diagnose. We have analyzed renal allografts in nonhuman primates to determine the relationship between alloantibodies and the graft pathology of late graft loss. Seventeen Cynomolgus monkeys were chosen from among those on several protocols for renal allotransplantation with mixed chimerism induction so that animals with and without alloantibodies were included. All animals received transient CD154 blockade and short-term cyclosporine treatment until day 28. Serial blood samples were tested for alloantibodies. Protocol biopsies and autopsy kidneys were scored for pathology and C4d deposition. Group 1, defined by complete lack of C4d deposition (24 tissue samples; 8 recipients), had no detectable alloantibodies (33 serum samples; 1-7 samples per recipient) and no evidence of chronic rejection. Three survived greater than 2 years with normal function and histology. Group 2, defined as having C4d deposition in peritubular capillaries, all made alloantibodies (100%), and most grafts later showed chronic allograft glomerulopathy (89%), and/or arteriopathy (89%). All grafts in Group 2 failed (3-27 months). Pathologic lesions of typical of chronic rejection in humans develop in monkeys, correlate with antecedent alloantibodies/C4d deposition and predict chronic rejection rather than durable accommodation.     

An 81-year-old man with personality change, dementia, and gait disturbance with diffuse leukoaraiosis of the cerebral white matter]

We report an 81-year-old patient with progressive dementia, disinhibition, and gait disturbance. He showed visuospacial disorientation, apathy, and gait disturbance at 76 years of age. When he was 77 years old, he was diagnosed Parkinson's disease and treated with the 1-dopa, the dopamine agonist, the amantadin, and the anti-cholinergic drug. These treatments didn't improve his motor disturbances. His motor disturbances, apathy, and abnormal behavior progressed gradually. He was admitted to the hospital at the age of 77. He was severely demented and akinetic. Sometime, violent behavior and hallucination were seen. The brain MRI showed frontotemporal lobe atrophy and severe leukoaraiosis of the frontal white matter. At 79 years of age, he became mute and bedridden. When he was 80 years old, large infarction occurred in his occipital lobe. He died due to renal failure and respiratory suppression at 81 years of age. His brain was examined pathologically. At the neurological CPC, the chief discussant arrived at the conclusion that his diagnosis was Binswanger's disease. Other possibilities discussed were FTD, CBD, and progressive subcortical gliosis. The post-mortem examination revealed diffuse white matter degeneration due to atherosclerotic change of the small artery, many lacunar infarctions, and severe infarction of the occipital lobe. These findings led the diagnosis of Binswanger's disease and cerebral infarction.     

Effects of pulsatile cardiopulmonary bypass on the renin-angiotensin-aldosterone system following open heart surgery

The effects of pulsatile cardiopulmonary bypass on the renin-angiotensin-aldosterone system and tissue metabolism, especially those which occur soon after surgery, were studied in 26 patients who required total cardiopulmonary bypass for longer than 60 minutes. These patients comprised 11 who underwent open heart surgery utilizing nonpulsatile cardiopulmonary bypass (Group I) and 15 who underwent open heart surgery utilizing pulsatile cardiopulmonary bypass (Group II). Plasma angiotensin II and serum aldosterene levels were significantly increased one and 5 hours postoperatively in Group I when compared with the preoperative values, whereas no significant elevations were observed in Group II. Plasma angiotensin II and serum aldosterone levels one hour postoperatively in Group II were significantly lower than those in Group I. Lactate levels in the arterial blood were significantly elevated, one and 5 hours postoperatively in both Groups I and II. Moreover, no significant difference was observed in the lactate levels between Groups I and II, one hour postoperatively. In the nonpulsatile group (Group I), plasma angiotensin II levels one hour postoperatively were correlated significantly with the duration of total cardiopulmonary bypass. In conclusion, pulsatile cardiopulmonary bypass offers significant advantages in terms of lower plasma angiotensin II and serum aldosterone levels, when compared with nonpulsatile cardiopulmonary bypass soon after open heart surgery requiring total cardiopulmonary bypass for longer than 60 minutes, however, it does not offer a definite advantage for tissue metabolism.     

Effect of hypertension on asymmetrical septal hypertrophy: an echocardiographic study

The effect of hypertension on asymmetrical septal hypertrophy was studied by echocardiography to differentiate idiopathic asymmetrical septal hypertrophy (ASH) from ASH with hypertension. One hundred eight patients with ASH proven by echocardiography were categorized in two groups; 53 patients with hypertension (greater than 160 systolic, greater than 95 diastolic) (hypertensive group: HT) and 55 patients with normal blood pressure (normotensive group: NT). Septal hypertrophy was classified as mid-portion (M-type), diffuse (D-type), and basal (B-type) hypertrophy by the long-axis view, and also diffuse (I-type), anterolateral (II-type), anteroseptal (III-type), and anterior septal (IV-type) by the short-axis view, respectively. Endomyocardial biopsy and left ventriculography were performed in 50 patients (18 hypertensives and 32 normotensives). In the hypertensive group, 45%, 30%, and 25% of cases had diffuse, basal and mid-portion hypertrophy, respectively. There was no case in the basal hypertrophy whose biopsy findings were compatible with hypertrophic cardiomyopathy. In the normotensive group, 78% and 22% of patients had midportion and diffuse hypertrophy, respectively, but none of them had the basal hypertrophy. Type IV was seen in only six patients in the normotensive group.